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Additive manufacturing has emerged as a promising approach for fabricating graded refractive index structures that control the electromagnetic response of radio frequency (RF) devices. However, current 3D printing methods cannot produce continuous gradients from multiple materials. Here, low‐loss graded dielectrics via active mixing of nanocomposite inks composed of block copolymers and oxide nanoparticles are designed and printed. By simultaneously tailoring their rheological, printing, and their local filler particle‐to‐polymer ratio using an active mixing printhead, a conductive microstrip‐graded substrate matching network with a gradually changing dielectric response, is created. In these printed devices, the impedance of the RF signal is controlled by the graded substrate rather than by varying the conductive microstrip geometry, enabling the fabrication of smaller RF devices. This approach enables the rapid design and fabrication of high‐performance RF devices with locally tunable dielectric properties.

The harsh radiation environment of space induces the degradation and malfunctioning of electronic systems. Current approaches for protecting these microelectronic devices are generally limited to attenuating a single type of radiation or require only selecting components that have undergone the intensive and expensive process to be radiation-hardened by design. Herein, we describe an alternative fabrication strategy to manufacture multimaterial radiation shielding via direct ink writing of custom tungsten and boron nitride composites. The additively manufactured shields were shown to be capable of attenuating multiple species of radiation by tailoring the composition and architecture of the printed composite materials. The shear-induced alignment during the printing process of the anisotropic boron nitride flakes provided a facile method for introducing favorable thermal management characteristics to the shields. This generalized method offers a promising approach for protecting commercially available microelectronic systems from radiation damage and we anticipate this will vastly enhance the capabilities of future satellites and space systems.